EP0242353A1 - Electric pressure detector provided with a leak indicator. - Google Patents
Electric pressure detector provided with a leak indicator.Info
- Publication number
- EP0242353A1 EP0242353A1 EP85904090A EP85904090A EP0242353A1 EP 0242353 A1 EP0242353 A1 EP 0242353A1 EP 85904090 A EP85904090 A EP 85904090A EP 85904090 A EP85904090 A EP 85904090A EP 0242353 A1 EP0242353 A1 EP 0242353A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pressure
- pressure chamber
- conductor track
- reference pressure
- chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/042—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point by using materials which expand, contract, disintegrate, or decompose in contact with a fluid
- G01M3/045—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point by using materials which expand, contract, disintegrate, or decompose in contact with a fluid with electrical detection means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
- G01L19/0061—Electrical connection means
- G01L19/0084—Electrical connection means to the outside of the housing
Definitions
- the invention relates to a pressure transmitter for generating electrical signals according to the preamble of the main claim.
- a pressure transmitter for generating electrical signals according to the preamble of the main claim.
- the sensor elements are attached in the edge region of a membrane which is obtained from a silicon semiconductor by spark erosion, by etching or other processes and which closes a reference pressure chamber to the medium under pressure (US Pat 4 079 508).
- the reference pressure chamber is closed under vacuum to measure absolute pressures.
- the signals emitted by the sensor elements or by a pressure switch are falsified as soon as the reference pressure chamber leaks. With these pressure transmitters, a leak in the reference pressure chamber can only be detected by a tach measurement when the sensor is serviced.
- the aim of the present solution is to monitor the tightness of the reference pressure chamber while the pressure transmitter is in use with the evaluation circuit connected.
- the pressure transmitter according to the invention with the characterizing features of the main claim has the advantage that the reference pressure chamber can be checked for air ingress at any time with the connected evaluation circuit.
- the conductor track which oxidizes when oxygen enters the reference pressure chamber represents a type of fuse which interrupts the measuring current of the sensor elements or a special monitoring circuit.
- Another advantage is that such monitoring of the reference pressure chamber means that pressure transmitters can also be used in safety-relevant parts, such as in tire pressure monitoring in motor vehicles.
- the proposed solution can be used not only for semiconductor sensors, but for all pressure transmitter systems that work with a reference pressure chamber.
- the conductor track to be interrupted by oxidation is applied to a substrate which also carries the sensor elements.
- the substrate is designed in a manner known per se in the area of the sensor elements as a pressure-dependent deformable membrane.
- the conductor track it is particularly expedient if, on the one hand, it has an electrically conductive region of the reference pressure chamber which is at reference potential, and on the other hand is connected to an electrically insulated feedthrough through the reference pressure chamber.
- the reference potential is applied to an annular conductor track of a printed circuit board which is soldered to the edge of a capsule which closes off the reference pressure chamber from the outside.
- FIG. 1 shows the pressure transmitter according to the invention with a capsule for the reference pressure chamber in an enlarged representation in cross section
- FIG. 2 shows the pressure transmitter from FIG. 1 without a capsule in a spatial representation.
- the pressure transmitter 10 shown in FIGS. 1 and 2 essentially consists of a semiconductor chip 9, for example of a silicon single crystal, on the surface of which four piezoresistive sensor elements 11 are arranged in the form of a resistance bridge circuit.
- the sensor elements 11, of which only two can be seen in the figures, are located on the edge of a membrane 12 which can be deformed by external forces and which is produced by removing the semiconductor material in a round or elliptical area 13 on the rear side of the pressure transmitter 10.
- the semiconductor chip 9 is firmly seated on a printed circuit board 14 by being soldered, glued or bonded there in a pressure-tight manner to an annular conductor track 15.
- the elliptical region 13 of the semiconductor chip 9 is located above a bore 16 in the printed circuit board 14 through which a medium under pressure, for example air, a gas or a liquid, reaches the membrane 12 in the direction of the arrow 17.
- a medium under pressure for example air, a gas or a liquid
- the reference pressure chamber 18 is closed off by the membrane 12 and by the printed circuit board 14 to the medium under pressure.
- the reference pressure chamber 18 is under vacuum.
- the capsule 19 is soldered or welded in a vacuum-tight manner to a further annular conductor track 20 on the printed circuit board 14.
- this conductor track 20 is set to a reference potential, a connection of the bridge circuit of the sensor elements 11 preferably also being connected to this conductor track 20.
- Another connection of the sensor elements 11 is connected via a connecting wire 21 to a contact pin 22 which is fastened in a pressure-tight manner in the circuit board 14 in a glass bushing 23.
- a conductor track 24 is applied to the semiconductor chip 9 of the pressure transmitter 10 in addition to the sensor elements 11, the material of which oxidizes so strongly when oxygen enters the reference pressure chamber 18 that the conductor track 24 is thereby interrupted electrically or in its resistance value is greatly changed.
- the conductor 24 is connected at one end via a connecting wire 25 to the reference potential, ringformi gene conductor 20 of the circuit board 14 and at its other end it is connected via a further connecting wire 26 to a further contact pin 27, which is also in a glass bushing 28th is inserted pressure-tight in the circuit board 14.
- both the sensor elements 11 and the conductor track 24 are used for monitoring the reference pressure chamber 18 is connected to an evaluation circuit, not shown.
- the conductor 24 is connected to a measuring circuit, via which each time the pressure transmitter 10 is started up, it can first be determined whether the conductor 24 is still intact or not. It is particularly advantageous to produce the conductor track 24 for monitoring the reference pressure chamber 18 from a material which, in the heated state, oxidizes so strongly in a short time due to the penetration of oxygen that the measuring circuit is thereby interrupted.
- the conductor 24 is therefore made in the example of nickel, which is initially heated by a measuring current to about 500 ° C. with each start-up of the pressure transmitter 10. The conductor track 24 is then checked for continuity. As soon as a leak now occurs in the reference pressure chamber 18, oxygen flows in and the measuring circuit with the conductor track 24 is interrupted when heated. The failure of the pressure transmitter 10 is determined and reported in this way with the evaluation circuit.
- the conductor track used for leak monitoring can also be arranged on the printed circuit board 14, on the one hand it is contacted with the annular conductor track 20 carrying the reference potential and on the other hand can be connected to the contact pin 27 of the leadthrough 28 via a connecting wire . It is also possible to insert the conductor track for leak monitoring directly into the power supply of the sensor elements 11, as a result of which one of the two bushings 22 and 28 in the printed circuit board 14 could then be omitted. In this case, the evaluation circuit would continuously monitor the vacuum chamber during operation possible.
- nickel other easily oxidizable metals, for example calcium, sodium or titanium, can also be used here.
- the use of a material which only oxidizes in the heated state has the further advantage that the pressure transmitter can also be processed or transported in air at room temperature during manufacture.
- a vacuum in the reference pressure chamber it is also possible to fill it with a pressurized gas, for example a noble gas, which does not cause oxidation of the conductor track. If the reference pressure chamber were to leak, this gas would flow out and then the oxygen in the air entering through the leak would interrupt the conductor path by oxidation.
- a pressurized gas for example a noble gas
- the solution principle can be used for semiconductor sensors, strain gauges, capacitive pressure sensors, inductive pressure sensors, Hall sensors and other pressure sensors, provided that they are provided with a reference pressure chamber.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
Le capteur de pression proposé engendrant des signaux électriques est muni d'éléments détecteurs (11) portés par une membrane (12) déformable en fonction de la pression et fermant une chambre de pression de référence (18) vis-à-vis le milieu sous pression. La chambre de pression de référence (18) constitue un espace exempt d'oxygène, de préférence un espace vide. Dans cette chambre une piste conductrice (24) est disposée sur un substrat; elle est si fortement oxydée lors d'une fuite dans la chambre de référence par l'introduction d'oxygène qu'elle est électriquement coupée. Pour indiquer une telle fuite dans la chambre de référence de pression (18) la piste conductrice (18) est connectée à un circuit de mesure. Cette solution peut être appliquée également à des détecteurs à semi-conducteur, à des bandes de mesure d'élongation, à des capteurs de pression capacitifs, inductifs, à effet Hall ou à d'autres capteurs de pression, pour autant que ceux-ci soient pourvus d'une chambre de pression de référence.The proposed pressure sensor generating electrical signals is provided with detector elements (11) carried by a membrane (12) deformable as a function of the pressure and closing a reference pressure chamber (18) vis-à-vis the medium under pressure. The reference pressure chamber (18) constitutes an oxygen-free space, preferably an empty space. In this chamber, a conductive track (24) is arranged on a substrate; it is so strongly oxidized during a leak in the reference chamber by the introduction of oxygen that it is electrically cut off. To indicate such a leak in the pressure reference chamber (18) the conductive track (18) is connected to a measuring circuit. This solution can also be applied to semiconductor detectors, elongation measuring strips, capacitive, inductive, Hall effect pressure sensors or other pressure sensors, as long as these are provided with a reference pressure chamber.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3447396 | 1984-12-24 | ||
DE19843447396 DE3447396A1 (en) | 1984-12-24 | 1984-12-24 | ELECTRIC PRESSURE |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0242353A1 true EP0242353A1 (en) | 1987-10-28 |
EP0242353B1 EP0242353B1 (en) | 1989-05-31 |
Family
ID=6253892
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85904090A Expired EP0242353B1 (en) | 1984-12-24 | 1985-08-13 | Electric pressure detector provided with a leak indicator |
Country Status (5)
Country | Link |
---|---|
US (1) | US4726233A (en) |
EP (1) | EP0242353B1 (en) |
JP (1) | JPS62501931A (en) |
DE (2) | DE3447396A1 (en) |
WO (1) | WO1986003835A1 (en) |
Families Citing this family (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0215140B1 (en) * | 1985-09-11 | 1989-04-26 | Kunz, Manfred | Pressure sensor |
DE3705901C2 (en) * | 1987-02-24 | 1996-12-12 | Siemens Ag | Pressure transducer |
IT1223710B (en) * | 1988-07-21 | 1990-09-29 | Marelli Autronica | VERY HIGH PRESSURE TRANSDUCER IN PARTICULAR FOR THE DETECTION OF THE PRESSURE OF A HYDRAULIC FLUID |
US5285690A (en) * | 1992-01-24 | 1994-02-15 | The Foxboro Company | Pressure sensor having a laminated substrate |
US5465626A (en) * | 1994-04-04 | 1995-11-14 | Motorola, Inc. | Pressure sensor with stress isolation platform hermetically sealed to protect sensor die |
WO1996022515A1 (en) * | 1995-01-19 | 1996-07-25 | Honeywell Inc. | Apparatus for detection of a diaphragm rupture in a pressure sensor |
US5844130A (en) | 1996-04-03 | 1998-12-01 | Ssi Technologies | Apparatus for maintaining a constant radial distance between a transmitting circuit and an antenna coil |
FR2787194B1 (en) * | 1998-12-11 | 2001-01-05 | Sagem | AUTOMOTIVE TIRE ACCELERATION DETECTOR |
US6422088B1 (en) | 1999-09-24 | 2002-07-23 | Denso Corporation | Sensor failure or abnormality detecting system incorporated in a physical or dynamic quantity detecting apparatus |
JP4062858B2 (en) * | 2000-04-27 | 2008-03-19 | 株式会社デンソー | Pressure sensor |
US6434456B1 (en) * | 2000-09-07 | 2002-08-13 | Kelsey-Hayes Company | High reliability pressure sensor |
DE10135568A1 (en) * | 2001-07-20 | 2003-02-06 | Endress & Hauser Gmbh & Co Kg | Differential or absolute pressure sensor has a hermetically sealed cap to protect measurement electronics from the external environment and prevent moisture ingress |
DE10319661A1 (en) * | 2003-05-02 | 2004-11-18 | Robert Bosch Gmbh | Encapsulated micro-sensor for pressure measurement, has a current conductor within its chamber that has at least two voltage taps to permit determination of a gaseous medium thermodynamic value to detect leaks in the encapsulation |
EP1533270A1 (en) * | 2003-11-21 | 2005-05-25 | Asulab S.A. | Method to test the hermeticity of a sealed cavity micromechanical device and the device to be so tested |
WO2006114882A1 (en) * | 2005-04-22 | 2006-11-02 | Mitsubishi Denki Kabushiki Kaisha | Gas tube arrestor and circuit device |
US7775118B2 (en) * | 2008-04-24 | 2010-08-17 | Custom Sensors & Technologies, Inc. | Sensor element assembly and method |
DE202009003677U1 (en) * | 2009-03-17 | 2010-04-29 | Porextherm-Dämmstoffe Gmbh | Indicator for detecting the ingress of air and / or moisture into a vacuum, pressure or protective gas packaging |
EP2312290B1 (en) * | 2009-10-16 | 2019-09-25 | First Sensor Mobility GmbH | Pressure sensor and use of same in a fluid tank |
JP5749510B2 (en) * | 2011-02-09 | 2015-07-15 | 株式会社アルバック | Sealed device |
RU2456564C1 (en) * | 2011-03-14 | 2012-07-20 | Открытое акционерное общество "Манотомь" | Indicating pressure gauge with induction sensors |
US8890308B2 (en) * | 2012-04-06 | 2014-11-18 | Freescale Semiconductor, Inc. | Integrated circuit package and method of forming the same |
JP6961447B2 (en) * | 2017-10-03 | 2021-11-05 | 旭ファイバーグラス株式会社 | Vacuum heat insulating material |
KR20210128097A (en) * | 2020-04-16 | 2021-10-26 | 주식회사 만도 | Braking system for vehicle |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4079508A (en) * | 1975-08-13 | 1978-03-21 | The Board Of Trustees Of The Leland Stanford Junior University | Miniature absolute pressure transducer assembly and method |
US4023562A (en) * | 1975-09-02 | 1977-05-17 | Case Western Reserve University | Miniature pressure transducer for medical use and assembly method |
JPS5524423A (en) * | 1978-08-10 | 1980-02-21 | Nissan Motor Co Ltd | Semiconductor pressure sensor |
DE2901636A1 (en) * | 1979-01-17 | 1980-07-24 | Leybold Heraeus Gmbh & Co Kg | Diaphragm pressure transducer assembly - has closed chamber containing displacement sensor and drying agent |
JPS5817421B2 (en) * | 1979-02-02 | 1983-04-07 | 日産自動車株式会社 | semiconductor pressure sensor |
US4661759A (en) * | 1984-08-16 | 1987-04-28 | Energy Research Corporation | Nickel-oxygen monitor cell system |
-
1984
- 1984-12-24 DE DE19843447396 patent/DE3447396A1/en not_active Withdrawn
-
1985
- 1985-08-13 US US06/921,049 patent/US4726233A/en not_active Expired - Fee Related
- 1985-08-13 WO PCT/DE1985/000272 patent/WO1986003835A1/en active IP Right Grant
- 1985-08-13 JP JP60503726A patent/JPS62501931A/en active Pending
- 1985-08-13 DE DE8585904090T patent/DE3570753D1/en not_active Expired
- 1985-08-13 EP EP85904090A patent/EP0242353B1/en not_active Expired
Non-Patent Citations (1)
Title |
---|
See references of WO8603835A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP0242353B1 (en) | 1989-05-31 |
US4726233A (en) | 1988-02-23 |
DE3570753D1 (en) | 1989-07-06 |
DE3447396A1 (en) | 1986-07-03 |
JPS62501931A (en) | 1987-07-30 |
WO1986003835A1 (en) | 1986-07-03 |
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